Anaesthesia for septic patients

Anaesthetic Management of Septic Patients: Short abstract. Evaluation of volume state and cardiac function. The septic patient coming for anaesthesia is usually in a hypodynamic or hyperdynamic state. In both situations the relative circulating blood volume is low due to capillary leak. Fluid resuscitation is therefore essential before the start of anaesthesia. Patients in sepsis and SIRS have impaired myocardial function. Measures to obtain cardiovascular stability. The optimisation of the volume state and the cardiovascular support with e.g. low dose noradrenaline (0.05-0.1µg/kg/min) and/or dopamine (3-5µg/kg/min) should be initiated before starting anaesthesia. These measures are important to avoid cardiovascular collapse during induction of anaesthesia. Several fluid regimens are advocated but no definite conclusion can be made with regard to superiority. It should be recommended to have an intra-arterial cannula to monitor blood pressure continuously. The need for extended monitoring of cardiovascular function is required at an earlier stage in a septic than in a non-septic patient since the response to treatment vary greatly. Regional anaesthesia. Many anaesthesiologists are reluctant to use regional anaesthesia in septic patients due to fear of neuroaxial infection. Some have advocated epidural rather than spinal anaesthesia since only the latter break the blood –brain barrier. This is an important concern but there is little evidence of the occurrence neither of septic episodes nor of meningitis after short-time use of epidural catheters or spinal anaesthesia. Induction of general anaesthesia. For all induction the timing of induction is vital for the effect on the cardiovascular stability. A slow induction can keep the patient stable while the same dose of a drug can cause major cardiovascular depression when given rapidly. Inhalation anaesthetics are less favourable than the intravenous drugs for induction due to the gastric retention often seen in septic patients. Maintenance of anaesthesia. Anaesthesia should be planned with consideration of the postoperative period. If the patient is supposed to be extubated postoperatively, drugs like remifentanil with a very short half-life - can be recommended for analgesia. The drug is easily titrated according to surgical stimulation but sufficient analgesia for the postoperative pain relief is mandatory. A drug like fentanyl in doses comparable to given in non-septic patients could be given in sufficient time before waking the patient. If the patient is in severe respiratory or multiorgan failure and the anaesthesio¬logist plans to continue mechanical ventilation, several analgesics dosed to effect, can be used. Inhalation anaesthetics are convenient. MAC of isoflurane and sevoflurane is reduced in septic animals. Pharmacokinetics. The pharmacokinetics of septic patients may change according to alteration in circulation and volume of distribution. The resulting pharmaco¬dynamics necessitates a very close monitoring of effect. The changes and disturbances in renal function are important for medication of ICU patients but is of less importance in the operating theatre. Bacterial cultures and antibiotics should not be forgotten! Some septic patients come directly to the operating theatre. The anaesthesiologist should re-evaluate the already initiated antibiotic therapy without taking independent actions. An operation can take several hours and if antibiotic therapy has not been initiated there may be a severe delay, which can be disastrous. Adequate samples for blood cultures and from infected areas can greatly facilitate future anti-infective therapy and outcome. Conclusion. The septic patient should be given the utmost care and should be treated by an experienced anaesthesiologist. A careful observation of the cardiovascular function is necessary and treatment should be tailored to the patient’s haemodynamic state.